• PNF and Movement
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• 제8권1호
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• pp.21-29
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• 2010

Purpose : The purpose of this research is to examine the effects of circuit weight training and aerobic exercise on the bodily formation and abdominal fat area of obese female college students. Methods : The female college students whose BMI is over $25kg/m^2$ were divided into the circuit weight training group and the aerobic exercise group and circuit weight training and aerobic exercise were conducted on the respective group five times a week. Resultlts : 1. The tendency of statistically significant reduction in weight, body fat percentage, and BMI was shown in both the circuit weight training group and the aerobic exercise group but there were no significant differences between these groups. 2. The tendency of statistically significant reduction in total abdominal fat area, and subcutaneous fat area was shown in both the circuit weight training group and the aerobic exercise group but there were no significant differences between these groups. 3. Visceral fat area was reduced more in the aerobic exercise group than in the circuit weight training group Conclusion : It was confirmed that exercise alone in the state of no dietary treatment being given could cause obese people bodily formation.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.290.1-290.1
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• 2016

Grapehen, a single atomic layer of graphite, has been in the spotlight and researched in vaious fields, because its fine mechanical, electrical properties, flexibility and transparence. Synthesis methods for large-area graphene such as chemical vaper deposition (CVD) and mechanical, chemical exfoliation have been reported. In particular, chemical exfoliation method receive attention due to low cost process. Chemical exfoliation method require reduction of graphene oxide in the process of exfoliation such as chemical reduction by strong reductant, thermal reduction on high temperature, and optical reduction via ultraviolet light exposure. Among these reduction methods, optical reduction is free from damage by strong reductant and high temperature. However, optical reduction is economically infeasible because the high cost of short-wavelength ultraviolet light sorce. In this paper, we make graphene-oxide and lanthanoid ion mixture aqueous solution which has highly optical absorbency in selective wevelength region. Sequentially, we synthesize reduced graphene oxide (RGO) using the solution and visible laser beam. Concretely, graphene oxide is made by modified hummer's method and mix with 1 ml each ultraviolet ray absorbent Gd3+ ion, Green laser absorbent Tb3+ ion, Red laser absorbent Eu3+ ion. After that, we revivify graphene oxide by laser exposure of 300 ~ 800 nm layser 1mW/cm2 +. We demonstrate reproducibility and repeatability of RGO through FT-IR, UV-VIS, Low temperature PL, SEM, XPS and electrical measurement.

• 한국환경복원기술학회지
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• 제12권2호
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• pp.61-72
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• 2009

This study aims to analyze the current situation of and issues in the structure of urban neighborhood parks and park facility installation in cities in Gyeonggi-do. Then, based on its findings, plans to improve the space structure of the parks were examined and suggested to raise the city environment improvement function and green area base function of urban parks and fully satisfy users' needs for pleasant rest, recreation and cultural activities. The findings showed that, within parks, the area of grass where access was restricted reached about 24.4% in average. In other words, only 75.6% of total park area could be freely used by park visitors. As for an improvement plan, the grass area where access is limited may be converted into a gras area that can be freely used to raise the park use area, which currently stands only at 75.6%, to 100%. The result of cross analysis through Chi-Square Test regarding lawn use as well as regarding (dis)agreement with reduction of lawn, based on the investigation of cognition, showed a significant agreement of park users with reduction of green areas. Therefore it is considered that lawn space must be reduced according the result of the analysis, to set up plans for facility space that would meet the desires of users. The analysis of user behaviors revealed that many of them used square spaces and walks; therefore it is considered that re-structuring of space is necessary according to local characteristics. This study also made some policy suggestion. urban parks must be a base of city green areas to counter climate changes. When developing a park creation plan, a user demand survey must be conducted in advance. In addition. grass construction methods should be improved to tolerate foot pressure.

• 한국산학기술학회논문지
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• 제12권4호
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• pp.1867-1875
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• 2011

이 논문에서는 저면적 256-point FFT 구조를 제안한다. 저면적 구현을 위하여 CSD(Canonic Signed Digit) 곱셈기 방식을 채택하여 구현하였다. CSD 곱셈기 방식을 효율적으로 적용하기 위해서는 곱셈연산의 가지 수가 적어야 하는데, 여러 알고리즘을 조사한 결과 Radix-$4^2$ 알고리즘이 곱셈연산의 가지 수가 적음을 발견하였다. 따라서 제안 구조는 Radix-$4^2$ DIF 알고리즘과 CSD 곱셈기 방식을 사용하였다. 즉 Radix-$4^2$ 알고리즘을 사용하여 4개의 스테이지에서 사용되는 곱셈연산의 가지 수를 최소화한 후에 각각의 곱셈연산 블록은 CSD 곱셈기를 사용하여 구현하였다. CSD 곱셈기 구현에서 공통패턴을 공유하여 덧셈기의 수를 줄일 수 있는 CSS(Common Sub-expression Sharing) 기술을 사용하여 구현면적을 더욱 감소시켰다. 제안된 FFT 구조를 Verilog-HDL 코딩 후 합성하여 구현한 결과, Radix-4를 사용한 구조와 비교하여 복소 곱셈기 부분의 29.9%의 cell area 감소를 보였고 전체적인 256-point FFT 구조에 대한 비교에서는 12.54% cell area 감소를 보였다.

• Design & Manufacturing
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• 제17권3호
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• pp.15-20
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• 2023

In the fine blanking process, which is a press operation known for producing parts with narrow clearances and high precision through the application of high pressure, die roll often occurs during the shearing process when the punch penetrates the material. This die roll phenomenon can significantly reduce the functional surface of the parts, leading to decreased product performance, strength, and fatigue life. In this research, we conducted an in-depth analysis of the factors influencing die roll in the curvature area of the fine blanking process and identified its root causes. Subsequently, we designed and experimentally verified a die roll reduction process specifically tailored for the door latch manufacturing process. Our findings indicate that die roll tends to increase as the curvature radius decreases, primarily due to the heightened bending moment resulting from reduced shape width-length. Additionally, die roll is triggered by the absorption of initial punch energy by scrap material during the early shearing phase, resulting in lower speed compared to the product area. To mitigate the occurrence of die roll, we strategically selected the Shaving process and carefully determined the shaving direction and clearance area length. Our experiments demonstrated a promising trend of up to 75% reduction in die roll when applying the Shaving process in the opposite direction of pre-cutting, with the minimum die roll observed at a clearance area length of 0.2 mm. Furthermore, we successfully implemented this approach in the production of door latch products, confirming a significant reduction in die roll. This research contributes valuable insights and practical solutions for addressing die roll issues in fine blanking processes.

• 한국도로학회논문집
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• 제17권4호
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• pp.11-18
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• 2015

PURPOSES: This study aims to evaluate the runoff reduction with permeable pavements using the SWMM analysis. METHODS: In this study, simulations were carried out using two different models, simple and complex, to evaluate the runoff reduction when an impermeable pavement is replaced with a permeable pavement. In the simple model, the target area for the analysis was grouped into four areas by the land use characteristics, using the statistical database. In the complex model, simulation was performed based on the data on the sewer and road network configuration of Yongsan-Gu Bogwang-Dong in Seoul, using the ArcGIS software. A scenario was created to investigate the hydro-performance of the permeable pavement based on the return period, runoff coefficient, and the area of permeable pavement that could be laid within one hour after rainfall. RESULTS : The simple modeling analysis results showed that, when an impervious pavement is replaced with a permeable pavement, the peak discharge reduced from $16.7m^3/s$ to $10.4m^3/s$. This represents a reduction of approximately 37.6%. The peak discharge from the whole basin showed a reduction of approximately 11.0%, and the quantity decreased from $52.9m^3/s$ to $47.2m^3/s$. The total flowoff reduced from $43,261m^3$ to $38,551m^3$, i.e., by approximately 10.9%. In the complex model, performed using the ArcGIS interpretation with fewer permeable pavements applicable, the return period and the runoff coefficient increased, and the total flowoff and peak discharge also increased. When the return period was set to 20 years, and a runoff coefficient of 0.05 was applied to all the roads, the total outflow reduced by $5195.7m^3$, and the ratio reduced to 11.7%. When the return period was increased from 20 years to 30 and 100 years, the total outflow reduction decreased from 11.7% to 8.0% and 5.1%, respectively. When a runoff coefficient of 0.5 was applied to all the roads under the return period of 20 years, the total outflow reduction was 10.8%; when the return period was increased to 30 and 100 years, the total outflow reduction decreased to 6.5% and 2.9%, respectively. However, unlike in the simple model, for all the cases in the complex model, the peak discharge reductions were less than 1%. CONCLUSIONS : Being one of the techniques for water circulation and runoff reduction, a high reduction for the small return period rainfall event of penetration was obtained by applying permeable pavements instead of impermeable pavement. With the SWMM analysis results, it was proved that changing to permeable pavement is one of the ways to effectively provide water circulation to various green infrastructure projects, and for stormwater management in urban watersheds.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2020년도 춘계학술대회
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• pp.132-132
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• 2020

• 공업화학
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• 제7권3호
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• pp.543-553
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• 1996

산소전극 촉매로서 페롭스카이트형 산화물을 사용하여 알칼리형 연료전지에서의 산소환원반응에 관하여 연구하였다. 능금산(malic acid)을 사용하여 고표면적의 페롭스카이트형 $La_{0.6}Sr_{0.4}Co_{1-x}Fe_xO_3$(x=0.00, 0.01, 0.10, 0.20, 0.35 및 0.50) 산화물을 제조하였으며, Fe 치환량과 암모니아수 첨가량에 따른 XRD 구조와 비표면적의 변화를 고찰하여 Fe와 암모니아간에 생성되어지는 착화합물이 페롭스카이트로의 구조안정화와 비표면적 증대의 주요임을 알았다. 그리고 페롭스카이트 단일상을 얻기 위해서는 다단계 승온처리가 필요했으며, XRD 실험결과 단순 정입방체상이 형성됨을 확인하였다. $La_{0.6}Sr_{0.4}Co_{1-x}Fe_xO_3$ 산화물을 촉매로 사용한 알칼리형 연료전지용 산소전극의 산소환원반응활성을 측정하기 위하여 순환 전압-전류법, 정전압-전류법, 전류단절법 등을 이용하였다. $La_{0.6}Sr_{0.4}Co_{1-x}Fe_xO_3$ 산화물에서 Fe의 치환비가 증가함에 따라, x=0.01에서 최소, x=0.20와 0.35 사이에서 최대의 산소환원활성(전류밀도)을 보였으며, 이와 같은 경향은 표면적의 변화와 무관하였다.

• Korean Chemical Engineering Research
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• 제60권4호
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• pp.620-629
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• 2022

가열 속도, 몰 공간속도, 질화반응온도 등 다양한 실험 조건을 변화하며 바나디움 산화물과 암모니아와의 승온 질화반응을 통하여 바나디움 산화질화물을 제조하여 특성분석을 수행하였으며 제조된 바나디움 산화질화물 상에서 암모니아 분해반응의 촉매 활성을 검토하였다. 제조된 촉매의 물리·화학적 특성을 알아보기 위하여 N₂ 흡착분석, X-선 회절분석(XRD), 수소 승온환원(H₂-TPR), 산소 존재 하 승온산화 (TPO), 암모니아 탈착 (NH₃-TPD), 투과전자현미경(TEM) 분석을 수행하였다. 340 ℃에서 5 m² g^-1의 낮은 비표면적을 갖는 V₂O₅의 환원에 의하여 V₂O₃ 으로의 변환은 미세 기공 형성에 의해 115 m² g^-1 높은 비표면적 값을 보여주었으며 그 이상의 질화반응 온도가 증가함에 따라 소결현상에 의해 지속적인 비표면적의 감소를 초래하였다. 비표면적에 가장 큰 영향을 미치는 질화반응 변수는 반응온도였으며, 단일 상의 VN_xO_y의 x + y 값은 질화반응온도가 증가함에 따라 1.5에서 1.0으로 근접하였으며 680 ℃의 높은 반응온도에서 입방 격자상수 a는 VN 값에 근접하였다. 본 실험 조건 중에 질화반응온도가 가장 높았던 680 ℃에서 암모니아 전환율은 93%로 나타났으며 비활성화는 관찰되지 않았다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권1호
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• pp.47-51
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• 2005

The bioelectrochemical reduction of nitrate in the presence of various mediators including methyl viologen and azure A was studied using a 3-electrode voltammetric system. The catalytic potential for the reduction of the mediators was observed in the reactor, which for methyl viologen and azure A were -0.74 V and -0.32 V, respectively, with respect to the potential of Ag/AgCl reference electrode. This potential was then applied to a working electrode to reduce each mediator for enzymatic nitrate reduction. Nitrite, the product of the reaction, was measured to observe the enzymatic nitrate reduction in the reaction media. Methyl viologen was observed as the most efficient mediator among those tested, while azure A showed the highest electron efficiency at the intrinsic reduction potential when the mediated enzyme reactions were carried out with the freely solubilized mediator. The electron transfer of azure A with respect to time was due to the adhesion of azure A to the hydrophilic surface during the reduction. In addition, the use of the adsorbed mediator on conductive activated carbon was proposed to inhibit the change in the electron transfer rate during the reaction by maintaining a constant mediator concentration and active surface area of the electrode. Azure A showed better than nitrite formation than methyl viologen when used with activated carbon.